guarantee vs assure

guarantee is a noun but assure is not a noun.

Word	Noun	Adjective	Verb	Adverb
guarantee	Yes	No	Yes	No
assure	No	No	Yes	No

As verbs, assure is a hypernym of guarantee; that is, assure is a word with a broader meaning than guarantee:

Other hypernyms of guarantee include promise.

As verbs, guarantee and assure are synonyms defined as:

Other synonyms of guarantee include ensure, insure, secure.

guarantee (noun)	assure (noun)
a written assurance that some product or service will be provided or will meet certain specifications
an unconditional commitment that something will happen or that something is true
a collateral agreement to answer for the debt of another in case that person defaults

guarantee (verb)	assure (verb)
give surety or assume responsibility	be careful or certain to do something; make certain of something
promise to do or accomplish	inform positively and with certainty and confidence
stand behind and guarantee the quality, accuracy, or condition of	assure somebody of the truth of something with the intention of giving the listener confidence
make certain of	make a promise or commitment
	make certain of